The GOP rolled fresh economic penalties on Iran into their alternative to Democrats’ veterans’ benefits bill, pressing for Congress to weigh in on diplomatic talks between global powers and Iran on scaling back the country’s nuclear program.

On Wednesday evening, Reid moved to cut off debate on the bill and block consideration of amendments to the legislation, dimming any chance of an immediate vote on Iran sanctions.

Senate Democrats have largely backed away from calling for an immediate vote on imposing Iran sanctions if the country breaks off ongoing negotiations or doesn’t adhere to a current, interim agreement. But Republicans have continued to press for a vote on sanctions legislation written by Sens. Robert Menendez (D-N.J.) and Mark Kirk (R-Ill.), proposing it be voted on as an amendment to a 2013 defense bill, as a condition for voting on military sexual assault legislation and as an amendment to the veterans bill.

“There is no excuse for muzzling the Congress on an issue of this importance to our own national security, to the security of Israel — our closest ally in the Middle East — and to international stability,” said Minority Leader Mitch McConnell (R-Ky.) on Wednesday morning. “This is that rare issue that should unite the two parties in common purpose. And there’s no question that it would, if the majority leader would simply drop his reflexive deference to a president whose foreign policy is focused on withdrawing from our overseas commitments.”

But Reid has sided with President Barack Obama on Iran, heeding the president’s warning that any vote on Iran sanctions — even conditional ones as suggested by McConnell — would shatter delicate diplomatic talks. The Democratic leader blamed Republicans for using sanctions as cover for their opposition to the veterans bill and for turning Iran into a partisan issue.

“The first amendment the Republicans demand is an unrelated issue on … Iran,” Reid said on Wednesday morning. “Republicans say they want to help veterans; a strange way of showing it. We introduced a bill that would do just that, Republicans immediately inject partisan politics into the mix.”